People spends hours at a time with their electronic devices—computers, telephones, music players, and the like. They like best those devices that are intuitive to use and whose interactions best meet their expectations regarding how machines should work. They interact with electronics through inputs and outputs from the devices, where the outputs generally are provided audibly and/or on a flat graphical display screen, and the inputs may occur via touch screens, joysticks, mice, four-directional keypads, and other such input mechanisms.
Fine distinctions in user interfaces can make a world of difference in a user's experience with a device. User interface options may be reduced for mobile devices, where full-sized keyboards or no keyboards at all are available. In such situations, intuitive interaction may be at a premium. The importance of such interaction may be even more pronounced with mobile devices, where the user needs to interact with a device using a single hand.